SS-1ED
SS-M9ED
SS-TW100ED
(1999 - 2001+)

Loudspeaker designed by Dan Anagnos (Polk Monitor).
ED stands for Extended Definition.
The SS-M9ED is a 60kg bass-reflex little monster with a demanding efficiency of 86dB but sporting superlative structure and componentry and a complex SS-TW100ED super-tweeter extending the frequency response to... 100kHz ! The original non-ED (SS-M9) version omits the super tweeter for a "regular" bandwidth and a pair of "regular" ears :)

The SS-M9ED was named SS-1ED in Japan and was also available in microscopic quantities without the piano-black finish (much better). The smaller siblings of the series (SS-M7, SS-M5, SS-M3) were export only and unheard of in Japan.

A glowing and very detailed review is available at Stereophile but I'll just add this: why was Sony always so quiet about its superlative gear ?